A computer network is a collection of interconnected computing devices that can exchange data and share resources. Example computing devices include routers, switches or other layer two (L2) devices that operate within the second layer of the Open Systems Interconnection (OSI) reference model, i.e., the data link layer, and routers or other layer three (L3) devices that operate within the third layer of the OSI reference model, i.e., the network layer. Network devices within computer networks often include a control unit that provides control plane functionality for the network device and forwarding components for routing or switching data units.
An Ethernet Virtual Private Network (“EVPN”) may be used to extend two or more remote L2 customer networks through an intermediate L3 network (usually referred to as a “provider network”), in a transparent manner, i.e., as if the intermediate L3 network does not exist. In particular, the EVPN transports L2 communications, such as Ethernet packets or “frames,” between customer networks via the intermediate L3 network. In a typical configuration, provider edge (“PE”) network devices (e.g., routers and/or switches) coupled to the customer edge (“CE”) network devices of the customer networks define label switched paths (LSPs) within the provider network to carry encapsulated L2 communications as if these customer networks were directly attached to the same local area network (LAN). In some configurations, the PE devices may also be connected by an IP infrastructure in which case IP/GRE tunneling or other IP tunneling can be used between the network devices.